production

production

1. casting

   • tupes of casting
     • liquid-> casting
     • viscous->plastic processe
     • powder-> metalurgy (sintering)
   • advantages
     • complex shapes
     • large products one piece
     • mostly cheap
     • isotropic final product
   • side notes
     • draft angles
     • hot material= bigger volume
       • alu-> 6.6 % an al ruler of 1 mm
         • LxBxH - 6,6 % = 1 meter
           • 1 mm on the ruler is 1,026 mm in real
   • types of molds
     • expendable
       • sand
         • no size limit
         • low tooling cost
         • course surface
         • mostly for metals
       • ceramic
         • high accuracy
         • high production rate
         • (shell moulding)
     • permanent ( metal molds)
       • metal molds
       • good finsish
       • high accuracy
       • limited complexicity
       • high mould cost
       • automatic
     • composit
       • both expendable and permanent

2. shaping and forming

   • continueus processes
     • rolling
       • flat
       • shape
       • metal rolling
         • max thickness depends on the friction coeficient
         • smaller diameters of rolls is better surface finish
     • extrusion
       • moderate to high equipment cost
       • high temp-> low ductillity
       • low temp-> high ductillity
       • pulled extrusion (wire)
         • always cold ( annealed first)
         • even deformation
         • anisotropic
         • hardens, so the thin part is as strong as the thick part
         • pipe is drawn with a floating mandril
   • discrete processes
     • forging
       • hot forging
         • lower forces
         • worse surface finish
         • anisotropic behavour
       • cold forging
         • good surface finish
         • high forces
         • crystal deformation
         • high stresses

3. separating processes

   • separating: removing material without changing structure hardly any material is lost
   • mechanical
     • with chips
       • sawing
       • grinding
         • wet
           • upto 50m/s
         • dry
           • up to 100m/s
         • more expensive than milling
         • very accurate
         • good for hard materials
         • grinding ratio:
           • G= dVworkpiece/dVdisc
       • milling
         • climb milling
           • clamps material down
         • conventional milling
           • better for hard top layer
         • pack mill
           • can drill
           • not symetrical
         • end mill
           • can not drill
           • comes in from the side
       • broaching
     • without chips
       • cutting
       • punching
         • punching
           • force liniar with
             • perimeter
             • shear strength
             • sheet thickness
           • punch inside outwards
           • diameter of punch should be less than the sheet thickness
         • blanking
         • parting
         • shear angle of the punch aprx 12 deg
   • physical
     • flame
     • plasma
       • high speed
       • strong ionisation of gass
       • smooth
     • laser
       • high temp
       • narrow cut
       • small heat affected zone
       • hampered by reflection and construction
       • problem: cuts through everything
       • laser drilling
         • very accurate
       • laser bending
         • bending with heat
         • badly controlled proces
     • independent of mechanical properties
     • based on concentrated energy
       • narrow cut
       • heat affected zone (bleu oxide)
   • wire edm
     • electrode wire dia 0,05 to 0,5 mm
     • speed up to 2,5 mm/sec
     • dieelectric fluid is not conductive
     • alternating current
     • gap with of 5-> 100 micrometer
     • electrical discharge machining
   • machining
     • tool charastaristics
       • toughness
       • thermal shock resistance
       • wear resistance
       • chemical stabillity and inertness
     • ISO classifications
       • example: HC-p 15
         • HC=coated
         • p= workpiece material
         • 15= mechanical load
     • cutting speed
       • tool steel
         • Vc<0,2 m/s
       • high speed steel
         • Vc 0,3 to 0,5 m/s
       • hard metal
         • Vc 1,5 to 3 m/s
       • coated carbide
         • Vc 6 m/s
       • ceramic
         • Vc 20 m/s
       • cubic boron nitride
         • Vc 5m/s
       • diamond
     • tool life
       • Vc * T ^n = C
         • Vc = cutting speed
         • T = tool life
         • ^n = constand
         • c = constant
   • ecm
     • electrical chemical machining
     • conductive fluid
     • fast
     • 5-20 Volt
     • 10.000 Amp
     • no toolwear
     • non alternating current
     • (electro etching)
     • conductive electrode
   • chemical machining
     • chemical attack
     • no current
     • (acid etch)

4. plastics

   • plastic= polymer with additive
     • fillers:
       • sawdust
       • chalk
     • plasticisers
       • soft and flexible
     • anti scission
       • protect for UV radiation
       • protect against oxigen
     • collorant
       • organic dye
     • flame retardent
       • chlorine
       • bromine
       • phosphorus
     • lubricants
       • reduce friction during production
       • reduce sticking during production
   • types of plastic
     • TP
       • thermoplast
     • TS
       • thermosetting
     • E
       • elastomer
   • extrusion blowmoulding
   • injection blowmoulding
   • rotational moulding

5. new processes

   • additive manufacturing
     • stereo lithiografie
       • printing with light beam in fluid
     • fast start of production
     • process gradually builds the prioduct
     • low production speed
     • small batches
     • complex shapes
     • no advantages of scale production
     • speeds up the design process -> prototyping
     • can be custom made
     • low amount of waste
     • weight reduction
     • only strength were required
       • topological optimisation
     • fused deposit manufacturing(3d printing)
     • laser sintering
     • 3d printing with gleu in chalk

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